The present invention relates to pre-filled vials, ampoules, carpules, or cartridges for administering injections of medicinal fluids to patients. More specifically, the invention relates to such devices having a retractable needle feature for rendering the device non-reusable and safely disposable.
Various types of medical devices employ a needle for piercing the skin of a patient for diagnostic or therapeutic purposes. One such device is a vial injector. Vial injectors utilize pre-filled vials that have a pre-measured dose of medication. The vial injector is used to inject the medication from the vial into a patient.
Handling of such needle-bearing medical devices after the needle is withdrawn from the patient can result in transmission of various pathogens, most notably human immune virus (HIV), to uninfected medical personnel, due to an inadvertent needle stick. Accordingly, it is desirable to provide a device for injecting medication from a pre-filled vial, wherein the injection needle is retracted into the housing of the device after use.
There are numerous retractable needle medical devices disclosed in the prior art. Typically, to effectuate retraction, the prior art devices require manual actuation by the operator. In many situations, such as an emergency situation, the operator is distracted or rushed so that the manual step necessary to effectuate retraction is not performed, either intentionally or unintentionally. In such instances, the used needle remains exposed, creating a risk of an inadvertent needle stick. Therefore, it would be desirable to provide an automatic needle retraction mechanism in which needle retraction is effectuated by normal operation of the device without the need to perform a separate manual step. It is further desirable to provide a device with a limited number of components so that the device can be produced cost effectively.
With the foregoing in mind, the present invention provides a medical device for injecting medicinal fluid from a fluid container, such as a vial, into a patient. The device includes a needle that is retracted automatically after use so that the contaminated sharpened tip of the needle is enclosed within the device to prevent inadvertent needle sticks.
The device includes a hollow housing having a generally open rearward end forming a socket. A vial containing a quantity of medicinal fluid is adapted to engage the socket. The needle for injecting the fluid is operable between a projecting position in which the sharpened tip of the needle projects forwardly from the housing and a retracted position wherein the sharpened tip is enclosed within the housing. A biasing element biases the needle toward the retracted position. A needle retainer releasably retains the needle in the projecting position. The needle retainer is operable between a locked position and an unlocked position. In the locked position, the needle retainer releasably retains the needle in the projecting position against the bias of the biasing element. In the unlocked position, the needle is released allowing the biasing element to displace the needle rearwardly. The vial cooperates with the needle retainer so that upon forward displacement of the vial, the vial engages the needle retainer displacing the needle retainer from the locked position to the unlocked position.